Neuraxial anesthesia and anticoagulation
Neuraxial anesthesia and anticoagulation:
• General principles
. – Avoid neuraxial anesthetic blocks (NAB) with preexisting coagulopathy or severe thrombocytopenia
. – Monitor for symptoms of spinal hematoma
. – Maintain a level that permits evaluation of neurologic status
. – Spinal hematoma must be diagnosed and treated within 8 hours
. – ITP causes “function” problems with platelets, not just “numbers” problems. Avoid neuraxial blocks and procedures.
• Standard unfractionated heparin
. – No heparin until 1 hour after NAB
. – Bloody tap? Probably cancel surgery
. – Remove catheters 1 hour before next dose and 2-4 hours after last dose
. – NAB okay in patients taking prophylactic SQ low-dose standard heparin
• Low molecular weight heparin
. – Spinals and epidurals can be used safely with LMWH with proper timing
. – Preoperative, prophylactic LMWH: place needle 10-12 hours after last LMWH dose
. – Specific preoperative therapy: place needle 24 hours after last LMWH
. – LMWH given 2 hours pre-operatively: NO BLOCK
. – Post-operative block before qd LMWH: catheter can remain, pull catheter 12 hours after last LMWH dose
. – Delay needle placement or catheter withdrawal until 12 hours from last low- dose LMWH and 24 hours after last high-dose LMWH
• Warfarin (Coumadin)
. – Check PT and INR before doing NAB if patient had prophylactic warfarin less that 24 hours before surgery
. – With chronic warfarin therapy, discontinue drug and check that PT and INR return to normal before NAB; risk of hematoma increases if INR > 1.5
• Antiplatelet drugs
. – NSAIDs don’t increase the risk of hematoma; NSAIDs plus other anticoagulants does increase the risk of hematoma
. – Stop ticlopidine, clopidogrel, and IIB/IIIA antagonists 7 to 14 days before NAB
• Fibrinolytic and thrombolytic drugs
. – Stop them 10 days before NAB
• Coagulation laboratory tests
. – PTT measures heparin activity
. – PT measures warfarin (Coumadin) activity
. – Coumadin inhibits production of vitamin K-dependent factors, which are 2, 7, 9, 10
. – INR (international normalized ratio) eliminates the problem of labs using different solvents
. a. 1.1 to 1.2 is normal
. b. No NAB if INR is greater than 1.5
. c. 2 to 3 is good for PE prophylaxis
. d. 3 to 4 is good for heart valve patients
• Plavix is an inhibitor of platelet aggregation’ ; it inhibits activation of the GP II/III complex
. – Patients must be off Plavix 7-10 days before surgery
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